Engine start button wiring diagram

[nikk0bacardi]

Hello, everyone!

I've been searching the forums and google for a wiring diagram, created by anyone, specific to the NSX for an engine start button. I found one thread that talks about it but because of the migration to this new system, the link is dead. I also found other links but they are for miatas. Additionally, I'm not using the s2k button. I tried entering the thread ID in the search bar but it did not find it.

Now, I currently have my engine start button wired up. It starts the car, but it's not in a consistent/smooth fashion. It will engage the starter, but the starter will not continue to turn the engine over. Instead, the starter will click, shut off, click, then turn the engine over. Sometimes it will click, click, click, then turn the engine over. It's intermittent in the way that it turns the engine over.


I doubt it's my main relay because I removed the enclosure and resoldered the pins as preventative maintenance. I'm thinking it may be because I'm using a SPST relay versus a SPDT relay. But I need to see a wiring diagram to confirm my issue. I have the service manual. But it only helped me identify the wires.

Your time and help is greatly appreciated!

 

[Old Guy]

You would need to provide a few more details beyond 'not using the s2k button'.

Are you trying to implement a push to start system or are you just using a pushbutton to replace the 'turn the key to start' motion. If you are just using a pushbutton to replace the turn the key to start function that is dead simple. You just connect the normally open contacts on the pushbutton to the Wht and Blk/Wht wires on the ignition switch. This requires that you still press the clutch pedal down to energize the starter cut relay. You can by-pass the clutch interlock switch to eliminate that if you want to. No relays required as long as you purchase a push button with sufficient current rating to operate the starter solenoid. You will need an external relay (SPST is adequate) with a n.o. contact if the current rating is insufficient. This system has absolutely no interlocks / safeties and will grind the starter if you hold the button too long or press it at the wrong time - just like the ignition key. The main EFI relay has absolutely nothing to do with the starter system. A 100% dead main EFI relay will not prevent the starter motor from operating - its just that the engine will not fire up.

A push to start system is a completely different pile of dung. Aftermarket push to start systems replace the ignition key switch assembly with a pushbutton and have relays to provide all the circuit switching that the ignition switch did. They require an engine speed signal to determine when to stop operating the starter and they are typically fitted with an RFID type fob for access because you are eliminating the key security function.

Indicate what you want to do and provide a schematic diagram of what you have done and then we can provide some guidance

 

[nikk0bacardi]

You would need to provide a few more details beyond 'not using the s2k button'.

Are you trying to implement a push to start system or are you just using a pushbutton to replace the 'turn the key to start' motion. If you are just using a pushbutton to replace the turn the key to start function that is dead simple. You just connect the normally open contacts on the pushbutton to the Wht and Blk/Wht wires on the ignition switch. This requires that you still press the clutch pedal down to energize the starter cut relay. You can by-pass the clutch interlock switch to eliminate that if you want to. No relays required as long as you purchase a push button with sufficient current rating to operate the starter solenoid. You will need an external relay (SPST is adequate) with a n.o. contact if the current rating is insufficient. This system has absolutely no interlocks / safeties and will grind the starter if you hold the button too long or press it at the wrong time - just like the ignition key. The main EFI relay has absolutely nothing to do with the starter system. A 100% dead main EFI relay will not prevent the starter motor from operating - its just that the engine will not fire up.

A push to start system is a completely different pile of dung. Aftermarket push to start systems replace the ignition key switch assembly with a pushbutton and have relays to provide all the circuit switching that the ignition switch did. They require an engine speed signal to determine when to stop operating the starter and they are typically fitted with an RFID type fob for access because you are eliminating the key security function.

Indicate what you want to do and provide a schematic diagram of what you have done and then we can provide some guidance

Thank you for taking the time to respond, Old Guy. The first paragraph you wrote is, essentially, what I currently have set up.
For reference, this is what I'm using.

This is the wireless device that makes the buttons function.

It came with an install sheet which I can't seem to find a copy of online. I'll provide a scan when I get the chance. Each button has two wires. Each set of wires is connected to a low-current relay within the wireless device. You can open the device and change the functionality of each button to be momentary or latched. My engine start button is momentary. The clutch pedal still needs to be depressed for the engine to start. I connected the corresponding wires to the relay that starts the car. Again, it is wired up to a SPST relay, but as you stated, it should be sufficient. I have not ruled out the possibility of the relay being faulty. It can't be the 12v battery because I replaced it last September and I always have it on a maintainer. Yesterday, it fired right up smoothly. But other times, it won't fire up smoothly.

At this point, I'm not sure if the wireless device could be the problem. But my cruise control and horn buttons work without issue. Ugh, I need to stop modding. But doing these kinds of mods makes me happy

Anyway, I will put together a diagram when I'm not swamped with homework. I would have to do some disassembling because I can't remember off the top of my head how I have it wired up. I completed this back in Aug 2021. You actually responded to my thread about another issue I was having when I was working on this, lol. I initially thought I used the incorrect gauge wire and assumed the wireless device was experiencing a voltage drop while starting the engine. IIRC, it needs 8 Amps. Anyway, I'll also provide a video to try and replicate the issue.

 

[Old Guy]

"Yesterday, it fired right up smoothly. But other times, it won't fire up smoothly."

If it worked correctly at least once, it is probably connected correctly. Your statement

"Instead, the starter will click, shut off, click, then turn the engine over. Sometimes it will click, click, click, then turn the engine over. It's intermittent in the way that it turns the engine over."

suggests that the way that it does not operate is also inconsistent. My gut reaction is that you may have an intermittent wiring fault (bad connection) or that the electronics has developed a problem. I am assuming that the control device picks up an engine speed signal of some kind to prevent starter grind / confirm that the engine is turning. Your "click, shut off, click" could be an indication that the speed signal has a problem. But, it could also be an indication that the electronics (which could be an intermittent wiring problem inside the module) has developed a problem.

Without knowing the internal schematic for the control device, it is practically impossible to advise on potential problems with it. However, if you can do a connection diagram post it and if any obvious candidates for a source of the problem float to the top I will advise.

 

[Pierce]

"Yesterday, it fired right up smoothly. But other times, it won't fire up smoothly."

If it worked correctly at least once, it is probably connected correctly. Your statement

"Instead, the starter will click, shut off, click, then turn the engine over. Sometimes it will click, click, click, then turn the engine over. It's intermittent in the way that it turns the engine over."

suggests that the way that it does not operate is also inconsistent. My gut reaction is that you may have an intermittent wiring fault (bad connection) or that the electronics has developed a problem. I am assuming that the control device picks up an engine speed signal of some kind to prevent starter grind / confirm that the engine is turning. Your "click, shut off, click" could be an indication that the speed signal has a problem. But, it could also be an indication that the electronics (which could be an intermittent wiring problem inside the module) has developed a problem.

Without knowing the internal schematic for the control device, it is practically impossible to advise on potential problems with it. However, if you can do a connection diagram post it and if any obvious candidates for a source of the problem float to the top I will advise.

A possible fault that I discovered recently may fit the hit and miss description of the starter that I had recently.
The starter was acting up. I would hear the solenoid click and sometimes a whirr but failure to strat. After a few attempts it would catch. Out came the starter and I installed new contacts. A simple job. It helped but did not completely cure the problem. I sourced a new plunger but rather than just toss it in I brought it to a shop where they rebuild starters.
I explained what was happening and asked for any feedback when he got a chance to look at it.
Bingo! He explained that the throw out of the starter itself was only coming out half way. He changed to the new plunger and everything ran fine and it all works as it should. He could not really offer an explanation of what was going on so I won't attempt one either but it might be a help in this case or maybe someone else can use this info.
I got the plunger from Sherco Auto and Marine.
Good luck.

 

[nikk0bacardi]

A possible fault that I discovered recently may fit the hit and miss description of the starter that I had recently.
The starter was acting up. I would hear the solenoid click and sometimes a whirr but failure to strat. After a few attempts it would catch. Out came the starter and I installed new contacts. A simple job. It helped but did not completely cure the problem. I sourced a new plunger but rather than just toss it in I brought it to a shop where they rebuild starters.
I explained what was happening and asked for any feedback when he got a chance to look at it.
Bingo! He explained that the throw out of the starter itself was only coming out half way. He changed to the new plunger and everything ran fine and it all works as it should. He could not really offer an explanation of what was going on so I won't attempt one either but it might be a help in this case or maybe someone else can use this info.
I got the plunger from Sherco Auto and Marine.
Good luck.

Thank you for taking the time to share a possible solution. I will post an update to see if doing this will fix my issue.